CN108604957B

CN108604957B - Repeater operation for delay sensitive reliable data exchange

Info

Publication number: CN108604957B
Application number: CN201780007947.7A
Authority: CN
Inventors: K·G·汉佩尔; V·D·帕克; 厉隽怿
Original assignee: Qualcomm Inc
Current assignee: Qualcomm Inc
Priority date: 2016-01-26
Filing date: 2017-01-20
Publication date: 2021-05-04
Anticipated expiration: 2037-01-20
Also published as: BR112018015117A2; EP3408958A1; US20170214493A1; AU2017211045B2; US10003438B2; AU2017211045A1; KR20180105657A; WO2017132064A1; CN108604957A

Abstract

Systems and methods for creating path diversity in rebroadcast data using wireless repeaters in wireless networks with delay-sensitive applications are disclosed. The first wireless communication device receives a data signal, which is transmitted from the second wireless communication device to the third wireless communication device on the first frequency resource. The first wireless communication device receives an ACK/NACK signal transmitted from the third wireless communication device to the second wireless communication device. The first wireless communication device determines whether the ACK/NACK signal is a NACK signal, and if so, transmits the data signal to the third wireless communication device at a second frequency resource during a third time period.

Description

Repeater operation for delay sensitive reliable data exchange

Cross Reference to Related Applications

The present application claims priority and benefit of united states non-provisional application serial No. 15/154,385, filed on day 5 and 13 of 2016, and united states provisional patent application serial No. 62/287,155, filed on day 1 and 26 of 2016, the entire contents of which are incorporated herein by reference, as set forth fully below and for all applicable purposes.

Technical Field

The present application relates to wireless communication systems, and more particularly to using wireless repeaters to create path diversity in rebroadcast data in wireless networks with mission critical applications.

Background

Wireless technology is common in sensor and control device networks. In mission critical sensors and control networks such as plant automation networks, fault tolerance is extremely low. In some cases, the fault tolerance may be as low as one billion packet loss. Thus, an appropriate error protection solution in many wireless networks may not be adequate for mission critical networks. Accordingly, there is a need for a system and method for functionally preventing errors in mission critical wireless networks.

Disclosure of Invention

The following presents a simplified summary of some aspects of the disclosure in order to provide a basic understanding of the discussed technology. This summary is not an extensive overview of all contemplated features of the disclosure, and is intended to neither identify key or critical elements of all aspects of the disclosure, nor delineate the scope of any or all aspects of the disclosure. Its sole purpose is to present some concepts of one or more aspects in a general form as a prelude to the more detailed description that is presented later.

In one aspect of the disclosure, a method of wireless communication includes receiving, at a first wireless communication device, a data signal transmitted from a second wireless device to a third wireless device on a first frequency resource. The method also includes receiving, at the first wireless communication device, an ACK/NACK signal transmitted from the third wireless device to the second wireless device. The method also includes determining, at the first wireless communication device, whether the ACK/NACK signal is a NACK signal. The method also includes transmitting a data signal from the first wireless communication device to the third wireless device on the second frequency resource during a third time period if the ACK/NACK signal is determined to be a NACK signal.

In a further aspect of the disclosure, a method of wireless communication includes receiving, at a first wireless communication device, a notification that a data signal is to be sent from a second wireless communication device to the first wireless communication device on a first frequency resource during a first time period. The method also includes transmitting, from the first wireless communication device, a NACK indicating that the data signal was not correctly received from the second wireless communication device. The method also includes receiving, at the first wireless communication device, a data signal on a second frequency resource from a third wireless communication device during a second time period.

In a further aspect of the disclosure, a first wireless communication device includes a transceiver configured to receive a data signal transmitted from a second wireless communication device to a third wireless communication device on a first frequency resource, the transceiver further configured to receive an ACK/NACK signal transmitted from the third wireless communication device to the second wireless communication device, and a processor configured to determine whether the ACK/NACK signal is a NACK signal. The transceiver is further configured to transmit a data signal to a third wireless communication device on a second frequency resource during a third time period if the ACK/NACK signal is determined to be a NACK signal.

In a further aspect of the disclosure, a first wireless communication device includes a transceiver configured to receive a notification that a data signal is to be transmitted from a second wireless communication device to the first wireless communication device on a first frequency resource during a first time period. The transceiver is further configured to transmit a NACK indicating that the data signal was not correctly received from the second wireless communication device, and receive the data signal from the third wireless communication device on the second frequency resource during the second time period.

In a further aspect of the disclosure, a computer-readable medium having program code recorded thereon includes code for causing a first wireless communication device to receive a data signal transmitted from a second wireless communication device to a third wireless communication device on a first frequency resource, code for causing the first wireless communication device to receive an ACK/NACK signal transmitted from the third wireless communication device to the second wireless communication device, code for causing the first wireless communication device to determine whether the ACK/NACK signal is a NACK signal, and code for causing the first wireless communication device to transmit the data signal to the third wireless communication device on a second frequency resource during a third time period if the ACK/NACK signal is determined to be a NACK signal.

In a further aspect of the disclosure, a computer-readable medium having program code recorded thereon includes code for causing a first wireless communication device to receive a notification that a data signal is to be sent from a second wireless communication device to the first wireless communication device on a first frequency resource during a first time period, code for causing the first wireless communication device to send a NACK indicating that the data signal was not correctly received from the second wireless communication device, and code for causing the first wireless communication device to receive the data signal from a third wireless communication device on a second frequency resource during a second time period.

In a further aspect of the disclosure, a first wireless communication device includes means for receiving a data signal to be transmitted from a second wireless communication device to a third wireless communication device on a first frequency resource, means for receiving an ACK/NACK signal transmitted from the third wireless communication device to the second wireless communication device, means for determining whether the ACK/NACK signal is a NACK signal, and means for transmitting the data signal to the third wireless communication device on a second frequency resource during a third time period if the ACK/NACK signal is determined to be a NACK signal.

In a further aspect of the disclosure, a first wireless communication device includes means for receiving a notification that a data signal is to be transmitted from a second wireless communication device to the first wireless communication device on a first frequency resource during a first time period, means for transmitting a NACK indicating that the data signal was not correctly received from the second wireless communication device, and means for receiving the data signal from a third wireless communication device on a second frequency resource during a second time period.

Other aspects, features and embodiments of the present invention will become apparent to those ordinarily skilled in the art upon review of the following description of specific, exemplary embodiments of the invention in conjunction with the accompanying figures. While features of the invention may be discussed with respect to certain embodiments and figures below, all embodiments of the invention can include one or more of the advantageous features discussed herein. In other words, while one or more embodiments may be discussed as having certain advantageous features, one or more of such features may also be used in accordance with the various embodiments of the invention discussed herein. In a similar manner, although example embodiments may be discussed below as device, system, or method embodiments, it should be understood that such example embodiments can be implemented in a variety of devices, systems, and methods.

Drawings

Fig. 1A illustrates a wireless communication network, in accordance with various aspects of the present disclosure.

Fig. 1B illustrates the wireless communication network of fig. 1A with obstructions and interference sources.

Fig. 2 is a block diagram illustrating an example controller in accordance with various aspects of the present disclosure.

Fig. 3A is a block diagram illustrating an example sensor or actuator apparatus in accordance with various aspects of the present disclosure.

Fig. 3B is a block diagram illustrating an example wireless repeater, in accordance with various aspects of the present disclosure.

Fig. 4 is an illustration of an example Downlink (DL) sequence over a network in accordance with various aspects of the disclosure.

Fig. 5 is an illustration of a time and frequency mapping of the DL sequence transmission of fig. 4.

Fig. 6 is an illustration of an example Uplink (UL) sequence over a network in accordance with various aspects of the disclosure.

Fig. 7 is an illustration of a time and frequency mapping of the UL sequence transmission of fig. 6.

Fig. 8 is a flow diagram of a method of reducing errors in a wireless network in accordance with some aspects of the present disclosure.

Detailed Description

The detailed description set forth below in connection with the appended drawings is intended as a description of various configurations and is not intended to represent the only configurations in which the concepts described herein may be practiced. The detailed description includes specific details for the purpose of providing a thorough understanding of various concepts. It will be apparent, however, to one skilled in the art that these concepts may be practiced without these specific details. In some instances, well-known structures and components are shown in block diagram form in order to avoid obscuring such concepts.

The techniques described herein may be used for various wireless communication networks such as CDMA, TDMA, FDMA, OFDMA, SC-FDMA and other networks. The terms "network" and "system" are often used interchangeably. A CDMA network may implement a radio technology such as Universal Terrestrial Radio Access (UTRA), CDMA2000, and so on. UTRA includes wideband CDMA (wcdma) and other variants of CDMA. CDMA2000 covers IS-2000, IS-95 and IS-856 standards. TDMA networks may implement radio technologies such as global system for mobile communications (GSM). The OFDMA network may implement radio technologies such as evolved UTRA (E-UTRA), Ultra Mobile Broadband (UMB), IEEE 802.11(Wi-Fi), IEEE 802.16(WiMAX), IEEE 802.20, Flash OFDMA (Flash-OFDMA), and the like. UTRA and E-UTRA are parts of the Universal Mobile Telecommunications System (UMTS). 3GPP Long Term Evolution (LTE) and LTE-advanced (LTE-A) are new versions of UMTS that use E-UTRA. UTRA, E-UTRA, UMTS, LTE-A and GSM are described in documents from an organization named "third Generation partnership project" (3 GPP). CDMA2000 and UMB are described in documents from an organization named "third generation partnership project 2" (3GPP 2). The techniques described herein may be used for the wireless networks and radio technologies mentioned above, as well as other wireless networks and radio technologies, such as next generation (e.g., 5 th generation (5G)) networks.

Embodiments of the present disclosure describe systems for ensuring reliability of wireless links in delay sensitive wireless applications, such as factory automation sensors and actuators for control loop applicationsA network. These networks rely on reliable data exchange for delay sensitive control loop applications. Such networks are therefore vulnerable to the obstruction of the primary communication path between the controller and the sensor devices, which is detrimental to plant operation. In such a system, up to 1x10 may be used^-9Because a single packet drop may cause catastrophic results such as robot manufacture and injury to bystanders. At least one wireless repeater is added to the network to create path and frequency diversity for retransmission of dropped packets. The repeater has global knowledge of the scheduling of transmissions for the controller and the plurality of sensor or actuator devices (SAs). The global scheduling data may include time and frequency resources scheduled for future transmissions as well as for past transmissions.

In one example, a repeater is presented that provides an alternative data path. The repeater acts as a repeater for retransmissions. The repeater overhears the initial transmission of the data packet and the ACK/NAK response. Based on which the link scheduled for retransmission is selected. The relay then determines the air interface resources for the deterministic based mapping of these retransmissions. The repeater then transmits the data jointly along with the retransmission of the original source (which may be the controller or sensor). Since the reason for the transmission failure is accompanied by some possibility due to interference generated in the unlicensed band, the repeater transmits in a band different from the band in which the original transmission has occurred. The repeater monitors all transmissions made between the controller and the plurality of SAs. The transmission includes at least a data signal, a data retransmission signal, and an ACK/NACK signal. For example, the transmissions may be organized according to an automatic repeat request (ARQ) or hybrid automatic repeat request (HARQ) error control system. The repeater can decode and cache the data and ACK/NACK signals. When the repeater decodes the NACK signal, it can determine that the transmission has failed and it can use its knowledge of the scheduling of the system to determine which of the controller or the multiple SAs lost the packet. The repeater can also determine which cached signal failed based on its knowledge of the schedule, and can re-encode the cached signal and retransmit the cached signal to the appropriate network device on a frequency and during a time period scheduled for retransmission.

Fig. 1A illustrates a wireless communication network 100 in accordance with various aspects of the present disclosure. The wireless network 100 may include a controller device 102, a number of sensor or actuator devices (SAs) 104, and at least one relay device 106. In some embodiments controller 102 may comprise a base station. For example, a base station may comprise an evolved node b (enodeb) in an LTE context environment. A base station may also be referred to as a base transceiver station or an access point. For simplicity of discussion, it will be referred to herein as a base station. The base station may be one of various types of base stations, such as macro, pico, and/or femto base stations.

The SA104 may include various types of wireless devices that incorporate sensors or meters to gather information, such as smart meters, temperature sensors, strain sensors, pressure sensors, fluid flow monitors, level line monitors, equipment monitors, weather and geological event monitors, position trackers, accelerometers, infrared sensors, and the like. The SA104 may also include various types of wireless devices that incorporate actuators to cause an attached device, such as a robot or other machine, to perform actions such as turning on or off or moving one or more components. In some embodiments, the SA104 may be an "internet of everything" (IOE) or "internet of things" (IOT) device. The relay 106 may include various types of wireless communication devices that incorporate wireless monitoring, data storage, and data transmission capabilities, including devices similar to those described above with respect to the controller 102 and the SA 104. In some instances, the relay 106 may be the controller 102 or the SA104 configured to perform the functions of the relay 106 as described herein. The SA104 and/or the repeater 106 may be low power devices designed to run on small batteries for extended periods of time. The SA 102 may be attached to various devices, such as robots in a factory automation system. Controllers 102 and SAs 104 may be dispersed throughout wireless network 100, and each controller 102, SA104, or relay 106 may be fixed or mobile. It is to be understood that more than one repeater 106 may be used in the network 100 to provide further path diversity.

There is a first wireless link 110 between the controller device 102 and the SA 104. The controller device 102 and the SA104 are actively sending data back and forth over the first wireless link 110. A second wireless link 112 exists between the repeater 106 and the controller 102 and SA 104. In this embodiment, the relay 106 monitors transmissions made between the controller 102 and the SA104 and between the relay 106 and the SA104, but transmits only when a retransmission is requested.

Referring now to fig. 1B, there is shown the network 100 of fig. 1A with an additional impediment 114, an interfering mobile device 116, and an interfering wireless Access Point (AP) 118. These new objects may cause the transmission over link 110 to fail. For example, the obstruction 114 may be an object located between one or more SAs 104 and the controller 102 that causes shadow fading in the link 110. The obstruction 114 may be a moving object, such as a person in a factory environment, a forklift, or a piece of automation equipment. The relay 106 may be located here such that it is unlikely that both the link 112 (between the relay 106 and the controller 102 and SA104) and the link 110 (between the relay controller 102 and SA104) are affected by an object such as the obstruction 114. In this way, the repeater 106 may provide path diversity to the network 100.

The mobile device 116 and the AP 118 may transmit using the same time and/or frequency resources as the controller 102 and the SA104, and thus may cause collisions in communications between the controller 102 and the SA 104. For example, an employee in a factory environment may walk through the network 100 carrying a mobile device 116, or a piece of factory equipment such as a high frequency welder that emits electromagnetic energy at high power in an unlicensed frequency band. The location of the repeater 106 may reduce interference from the mobile device 116 and the AP 118 due to fading alone. Furthermore, retransmissions in the system can be performed in a licensed frequency band, thus greatly reducing the possibility of interference during retransmissions.

Embodiments of the present disclosure are directed to any type of modulation scheme, but Frequency Division Multiplexing (FDM) is used as a representative modulation for data transmission in the downlink from the controller 102 to the SA104, and in the uplink from the SA104 to the controller 102. FDM is a multi-carrier modulation technique that partitions the overall system bandwidth into multiple frequency sub-bands, carrier frequencies, or channels. With FDM, each channel may be modulated with data.

The controller 102 may periodically send synchronization signals to the SA104 and the repeater 106. These synchronization signals are used to enable the SA104 and the repeater 106 to periodically synchronize their local clocks with the clock of the controller 102. This may be useful because their clocks may be less accurate due to the low power requirements imposed on the SA104 and the repeater 106. Thus, as time passes, the clocks for the SA104 and repeater 106 may be relative to the clocks of the controller 102, and the controller 102 may be a higher power device that tends to be more accurate and stable. Due to the drift, an offset may occur between the time the receiver of a given SA104 or repeater 106 is woken up to listen for the signal from the controller 102 and the time the receiver of the given SA104 or repeater 106 actually receives the signal from the base controller 102. If the drift becomes large enough, a given SA104 or repeater 106 will no longer be able to decode signals received from the controller 102. The synchronization signal provides information that allows the SA104 or repeater 106 to re-synchronize with the clock of the controller 102.

For example, the synchronization signal may be transmitted periodically at a pre-specified time interval that is known to the SA104 and the repeater 106. This may be established, for example, at an initially set time such as when the SA104 or repeater 106 is attached to the network via the controller 102. Alternatively or additionally, the controller 102 may establish the periodicity of the synchronization signals and at what frequency and time the synchronization signals will be sent, placing them in sleep mode with commands sent to the SA104 and the repeater 106. The synchronization signal may be embedded within an FDM downlink waveform that includes other information (such as data or control information) for one or more other SAs 104. The synchronization signal may be broadcast to all SAs 104 within the range of the FDM downlink waveform and modulated according to a different modulation scheme than the modulation scheme used for the remaining FDM downlink waveform. The SA104 and repeater 106 within the network 100 may wake up at a pre-specified time at which the synchronization signal is broadcast to re-synchronize with the clock of the controller 102, as described above.

According to further embodiments of the present disclosure, the controller 102 and each SA104 within the network 100 may be assigned a particular set of resources (e.g., frequency carriers and time slots) at which they transmit or listen for data, ACK/NACK signals, or other signals used by the appropriate protocol. This information is referred to as global scheduling data, or global scheduling information. The global schedule data is made known to the controller 102, SA104, and repeater 106. In some embodiments, controller 102 allocates resources for network 100.

The controller 102 may periodically send global schedule data to the SA104 and the repeater 106. The scheduling information may include a mapping of the time and frequency resources allocated to the controller 102 and SA104 for transmission, as well as the types of transmissions scheduled for those resources. For example, the schedule may indicate that a particular SA104 is scheduled to transmit data to the controller 102 on a first frequency during a first time slot, that the controller 102 is scheduled to transmit an ACK/NACK signal on a second frequency in a second time slot, that a third time slot and a third frequency are reserved for potential data retransmission from the SA104 to the controller 102, and that a fourth time slot and a fourth frequency are reserved for an ACK/NACK signal for the retransmitted data.

The global scheduling information may allow at least repeater 106 to determine what signals it is monitoring, which devices it is monitoring which transmit signals, and for which devices those signals are intended. Repeater 106 may determine the time slots during which signals are monitored and the frequencies over which signals are monitored based on the schedule. Further, with the complete scheduling information, the repeaters 106 may operate during the scheduled retransmission time period and on the scheduled retransmission frequency to retransmit any dropped packets to their intended recipients. The received retransmitted packet will look the same to the receiver as the packet it expects to receive from the sending device. Since the original transmitting device (e.g., controller 102 and SA104) will also retransmit the data autonomously, the likelihood of any subsequent retransmissions is increased by the presence of the repeater 106.

Similar to the synchronization signal, the scheduling information may be transmitted periodically at a pre-specified time interval that is made known to the SA104 and the repeater 106. The scheduling data may be established at the time the system is initiated, and new scheduling data may be periodically transmitted to maintain unbroken scheduling data at all devices in the network 100. According to some embodiments of the present disclosure, a base station external to the controller 102 may perform the above functions of transmitting the synchronization signal and the global scheduling data to all devices in the network 100, including the controller 102, the SA104, and the repeater 106. As described above with reference to fig. 1A, such base stations may include enodebs, and the base station may be one of various types of base stations, such as macro, pico, and/or femto base stations.

Fig. 2 is a block diagram illustrating an example controller 102, according to an embodiment of the present disclosure. The controller 102 may include a processor 202, a memory 204, a scheduling module 208, a transceiver 210, and an antenna 216. For example, these elements may communicate with each other directly or indirectly via one or more buses. As mentioned above with reference to fig. 1A or 1B, the controller 102 may communicate with a plurality of SAs 104 and with the repeater 106.

The transceiver 210 may include a modem subsystem 212 and a Radio Frequency (RF) unit 214. Transceiver 210 is configured to bidirectionally communicate with other devices, such as one or more UEs 120 and LP IOEs 130. Modem subsystem 212 may be configured to modulate and/or encode data according to a Modulation and Coding Scheme (MCS), such as a Low Density Parity Check (LDPC) coding scheme, a turbo coding scheme, a convolutional coding scheme, and/or the like.

The RF unit 214 may be configured to process (e.g., perform analog-to-digital conversion or digital-to-analog conversion, etc.) modulated/encoded data from the modem subsystem 212 (on transmissions to the outside) or transmissions originating from another source, such as the SA104 or repeater 106. Although shown as integrated together in transceiver 210, modem subsystem 212 and RF unit 214 may be separate devices coupled together at controller 102 to enable controller 102 to communicate with other devices.

The RF unit 214 may provide modulated and/or processed data, e.g., data packets, to the antenna 216 for transmission to one or more other devices, such as the SA 104. After the transceiver 210 receives the FDM information with the synchronization, data, and/or ACK/NACK embedded therein from the scheduling module 208, the modem subsystem 212 may modulate and/or encode the identification information in preparation for transmission. RF unit 214 may receive the modulated and/or encoded data packets and process the data packets before passing them to antenna 216. For example, this may include transmission of data messages to one or more SAs 104 in accordance with embodiments of the present disclosure. The antenna 216 may also receive data messages transmitted from the SA104 or the repeater 106 and provide the received data messages for processing and/or demodulation at the transceiver 210. As shown, the antenna 216 may include multiple antennas of similar or different designs to facilitate maintaining multiple transmission links.

Fig. 3A is a block diagram of an exemplary SA104, in accordance with an embodiment of the present disclosure. SA104 may include a processor 302, a memory 304, a modem 308, a transceiver 310, an RF front end 314, one or more antennas 320, and one or more sensors 322 and/or actuators 324. These elements may be in communication with each other, directly or indirectly, e.g., via one or more buses. As mentioned above with reference to fig. 1A or 1B, the SAs 104 may communicate with the controller 102 and other SAs 104 within range.

The processor 302 may include a CPU, DSP, ASIC, controller, FPGA device, another hardware device, firmware device, or any combination thereof configured to perform the operations described herein with reference to the SA104 set forth in fig. 1A-1B above. The processor 302 may also be implemented as a combination of computing devices, e.g., a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration.

The memory 304 may include cache memory (e.g., cache memory of the processor 302), RAM, MRAM, ROM, PROM, EPROM, EEPROM, flash memory, solid state memory devices, one or more hard drives, other forms of volatile and non-volatile memory, or combinations of different types of memory. In an embodiment, memory 304 includes a non-transitory computer-readable medium. The memory 304 may store instructions 306. The instructions 306 may include instructions that, when executed by the processor 302, cause the processor 302 to perform the operations described herein with reference to the SA104 in connection with embodiments of the present disclosure. The instructions 306 may also be referred to as code, which may be broadly interpreted to include any type of computer-readable statements as discussed above with reference to FIG. 2.

Modem subsystem 308 may be configured to modulate and/or encode data according to a Modulation and Coding Scheme (MCS), such as a Low Density Parity Check (LDPC) coding scheme, a turbo coding scheme, a convolutional coding scheme, or the like.

Transceiver 310 may include a transmitter and a receiver and any other components to allow for the transmission and reception of data, such as to process (e.g., perform analog-to-digital conversion or digital-to-analog conversion, etc.) modulated/encoded data from modem subsystem 308 (on an external transmission) or a transmission originating from another source, such as SA104 or repeater 106. For the transmitter, this may include digital to analog conversion, a local oscillator, and upconversion of the baseband signal to a selected transmission frequency, to name a few. For a receiver, this may include a down-converter to place the received signal at baseband, a baseband filter, and an analog-to-digital converter, to name a few.

The RF front end 314 may include a filter 318, which filter 318 may be, for example, a band pass filter for filtering out-of-band signals. The RF front end 314 may also include an impedance matching circuit and amplifier 316. Although shown separately, as will be appreciated, some aspects described above with respect to the transceiver 310 may be performed by the RF front end 314 (e.g., up-conversion, down-conversion, and mixing) and vice versa. The RF front end 314 may provide modulated and/or processed data, e.g., data packets, to the antenna 320 for transmission to the controller 102 or other SA 104.

The antenna 320 may include one or more antennas of similar or different designs to maintain single or multiple transmission links, respectively. After modulation and encoding from modem subsystem 308 and amplification at RF front end 314, antenna 320 of LP IOE 130 may transmit data provided from transceiver 310. The antenna 320 of the SA104 may also receive data from multiple sources, including from the controller 102. The antenna 320 may feed the received data to the RF front end 314.

For example, the one or more sensors 322 may include smart meters, temperature sensors, strain sensors, pressure sensors, fluid flow monitors, level line monitors, device monitors, weather and geological event monitors, position trackers, accelerometers, infrared sensors, and the like. For example, the one or more actuators 324 may operate to cause an attached device or component to perform a particular action such as turn on or off, move in a particular manner (including translation, rotation, and/or combinations thereof), and/or perform other functions associated with the SA104 or with a system in which the SA is implemented. The one or more actuators 324 may include electric, pneumatic, hydraulic, and/or mechanical actuators.

Fig. 3B is a block diagram of an exemplary repeater 106, in accordance with an embodiment of the present disclosure. In many aspects, the repeater 106 may be similar to the SA 104. The repeater 106 or repeater 106 may include a processor 302, a memory 304, a modem 308, a transceiver 310, an RF front end 314, one or more antennas 320, and one or more sensors and/or actuators 322. These elements may be in communication with each other, directly or indirectly, e.g., via one or more buses. As mentioned above with respect to fig. 1A or 1B, the repeater 106 may communicate with the controller 102 and other SAs 104 within range.

The processor 302 may include a CPU, DSP, ASIC, controller, FPGA device, another hardware device, firmware device, or any combination thereof configured to perform the operations described herein with reference to the SA104 set forth above in fig. 1A-1B. The processor 302 may also be implemented as a combination of computing devices, e.g., a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration.

The memory 304 may include cache memory (e.g., cache memory of the processor 302), RAM, MRAM, ROM, PROM, EPROM, EEPROM, flash memory, solid state memory devices, one or more hard drives, other forms of volatile and non-volatile memory, or combinations of different types of memory. In an embodiment, memory 304 includes a non-transitory computer-readable medium. The memory 304 may store instructions 306. The instructions 306 may include instructions that, when executed by the processor 302, cause the processor 302 to perform the operations described herein with reference to the SA104 in connection with embodiments of the present disclosure. The instructions 306 may also be referred to as code, which may be broadly interpreted to include any type of computer-readable statements as discussed above with respect to FIG. 2. According to various aspects of the present disclosure, the memory 304 may further store cached data 307. For example, the received data signals and/or the received ACK/NACK signals may be stored in the memory 304 as cached data 307.

The transceiver 310 may include a transmitter and a receiver and any other components to allow for the transmission and reception of data, such as to process (e.g., perform analog-to-digital conversion or digital-to-analog conversion, etc.) modulated/encoded data from the modem subsystem 308 (on an external transmission) or a transmission originating from, for example, the SA104 or the controller 102. For the transmitter, this may include digital to analog conversion, a local oscillator, and upconversion of the baseband signal to a selected transmission frequency, to name a few. For a receiver, this may include a down-converter that places the received signal at baseband, a baseband filter, and an analog-to-digital converter, to name a few.

The antenna 320 may include one or more antennas of similar or different designs to maintain single or multiple transmission links, respectively. After modulation and encoding from modem subsystem 308 and amplification at RF front end 314, antenna 320 of LP IOE 130 may transmit data provided from transceiver 310. The antenna 320 of the repeater 106 may also receive data from multiple sources, including from the controller 102. The antenna 320 may feed the received data to the RF front end 314.

In an exemplary embodiment, the repeater 106 can wake up at a pre-designated, first time to listen for synchronization signals on a designated, pre-determined frequency. The repeater 106 may correlate the signal with a stored code for the synchronization signal and, based on the comparison, adjust a clock offset local to the repeater 106 (which may be less accurate due to the low power nature of the device) to a time aligned with the clock of the controller 102 (which may be more accurate).

In a further exemplary embodiment, the repeater 106 may wake up at a pre-specified, second time to listen for the global scheduled data signal on a specified, pre-determined frequency. The repeater 106 may have stored an identifier or fingerprint for the global scheduling data signal in the memory 304 or elsewhere. The repeater 106 may compare the received global schedule data signal to the stored fingerprint to determine that global schedule data has been received. The repeater 106 may store global scheduling data for use in further embodiments described below. In alternative embodiments, the global scheduling data may be predetermined via a standard or may be configured on the repeater 106.

In a further exemplary embodiment, the repeater 106 may wake up at a pre-designated, third time to listen on a designated, predetermined frequency for data transmissions or ACK/NACK signals sent between the controller 102 and the SA 104. In this embodiment, the pre-specified time and frequency are based on global scheduling data received from the controller 102, as described above. For example, the repeater 106 will wake up and listen during the time slots and on the frequencies scheduled for data and ACK/NACK transmissions.

During the time slots scheduled for data transmission, as the antenna 320 obtains information from the environment, the transceiver 310 will decode the data signal so that the repeater 106 can cache the data signal. As the antenna 320 obtains information from the environment during the time slot scheduled for the ACK/NACK signal, the transceiver 310 compares the information to the stored codes for the ACK and NACK. The transceiver 310 may determine whether an ACK or NACK is received if the correlation value is less than (or less than/equal to) a predetermined threshold correlation value for the ACK or NACK. If an ACK is received, the repeater 106 may determine that it does not need to retransmit any data and may return to sleep mode until the next scheduled data transmission slot.

If a NACK is received, the repeater 106 may sleep until a time period scheduled for retransmission of the associated data signal that has been cached in the repeater 106. The repeater 106 will wake up at the retransmission time period and the transceiver 310 will re-encode the cached data and retransmit the data to the SA104 or controller 102 to which it is destined. The relay 106 may determine when to retransmit and to which SA104 or controller 102 to send based on the global scheduling data. In an exemplary embodiment, the retransmission occurs in a different frequency band than the original transmission, thus providing frequency diversity compared to the original, failed data transmission, and reducing the likelihood of failure during retransmission. For example, the initial data transmission may be on an unlicensed frequency band, while the retransmission is on a licensed frequency band. Since the licensed band requires paid-for licenses, the licensed band is typically less crowded than the unlicensed band, and thus the possible interference will be much lower. In delay sensitive applications, it is cost effective to pay a license fee for retransmissions over a licensed frequency band in order to adequately secure the retransmissions from interference. The repeater is time synchronized to a network maintaining a first frequency band and a second frequency band using a time synchronization frame structure, where each frame includes a first slot for initial transmission of information, a second slot for ACK feedback, and a third slot for retransmission of information. The relay uses resource partitioning to support multiple links in a first frequency band and a second frequency band. The repeater establishes a mapping between resources used by each link in the first, second and third time slots in the first and second frequency bands. The relay receives information transmitted in a first time slot in a first frequency band for a subset of links based on resource partitioning. The relay receives feedback (i.e., ACK/NACK) in the second time slot about a link having a successful first slot transmission by using a resource mapping between the first time slot and the second time slot. The repeater selects links with unsuccessful first slot transmissions, re-encodes information received in the first slots of the links, and uses the mapping to determine resources in the third slots in the second frequency band used by the links. Further, the relay transmits information on resources in a third time slot on a second frequency band.

Referring now to fig. 4, an exemplary Downlink (DL) sequence 400 over the network 100 is shown. In the first slot 402 of the DL sequence 400, two of the three DL transmissions from the controller 102 to the SA104 fail. The two failed

transmissions

404 and 406 are on frequencies f1 and f2 and are intended for the first SA104 and the second SA104, respectively. These failures may be due to obstructions, signal interference, etc., but this cannot be determined by the system. The third transmission 408 over the frequency f3 successfully reaches the third SA 104. The frequencies f1, f2, and f3 may be in unlicensed bands. The repeater 106 monitors all three

transmissions

404, 406, and 408. As described above, the repeater 106 may determine that the time slot 402 is designated for data transmission from the controller 102 to the SA104 based on the global scheduling information, and may further determine that the transmission 404 over f1 is to the first SA104, the transmission 406 over f2 is to the second SA104, and the transmission 408 over f3 is to the third SA 104. The repeater 106 will decode and cache the monitored data signal, e.g., cached data 307 as described above with reference to fig. 3B. In some embodiments, the repeater 106 will only cache received signals that it recognizes as data signals after decoding.

In the second slot 402 of the DL sequence 400, the first SA104 and the second SA104 that did not receive their expected data transmissions send

NACK signals

410 and 412 to the controller 102 over frequencies f4 and f5, respectively. The third SA104 that received its expected data signal sends an ACK signal 414 to the controller 102 over frequency f 6. The frequencies f4, f5, and f6 may be in unlicensed bands. The repeater 106 monitors and decodes these NACK and ACK signals. Based on the global scheduling data, the controller 102 and the relay 106 can determine that the

NACKs

410 and 412 received on frequencies f4 and f5 are from the first SA104 and the second SA104, respectively, and the ACK 414 received on frequency f6 is from the third SA 104. Receipt of the

NACKs

410 and 412 indicates to the controller 102 and the relay 106 that a retransmission of the associated data signal is requested.

In the third slot 402 of the DL sequence 400, the controller 102 and repeater 106 make any requested retransmissions. Both the controller 102 and the relay 106 may determine from the received

NACKs

410 and 412 in combination with the global scheduling data that the first SA104 and the second SA104 are requesting such that their data signals are retransmitted. The controller 102 and the repeater 106 know from the global scheduling data that the frequencies f7 and f8 are allocated for retransmission to the first SA104 and the second SA104 during the third slot 402. The controller 102 and the repeater 106 thus retrieve the original data signals from their caches, re-encode the data signals, and retransmit the data signals as

retransmissions

416 and 418 to the first SA104 and the second SA104, respectively, at frequencies f7 and f8, respectively. The frequencies f7 and f8 may be in licensed bands. In this embodiment, the first SA104 and the second SA104 successfully receive their retransmitted data signals. In other embodiments, if the repeater 106 does not receive a NACK, the repeater 106 may determine that there is no need to store the data signal received in the second time slot 402. Thus, the repeater 106 may delete data signals from the cached data 307, mark the data signals as rewritable, or otherwise free up memory resources for other purposes.

Thus, in the fourth slot 402 of the DL sequence 400, the first SA104 and the second SA104 send

ACK signals

420 and 422 over frequencies f10 and f11, respectively, to the controller 102. The repeater 106 monitors the ACK signals 420 and 422 on frequencies f10 and f11, decodes the signals, and determines from the global scheduling data that the signals must have been transmitted by the first SA104 and the second SA 104. Both the controller 102 and the repeater 106 determine from the received

ACK signals

420 and 422 that the retransmission was successful and that no further retransmission was requested. In other examples, one or more of the retransmissions may fail and both the controller 102 and the repeater 106 may make a second, third, or more retransmissions on different frequencies and/or in different time slots until the data is successfully received. When the system is initiated, the maximum number of retransmissions to attempt may be set across all devices in the network 100. In some embodiments, this number may be updated over time by transmissions from the controller 102 to the SA104 and/or the relay 106. Once the ACK signals 420 and 422 have been decoded at the controller 102 and the repeater 106, the repeater 106 may delete the data signal from the cached data 307, mark the data signal as rewritable, or otherwise free up memory resources for other purposes.

Referring now to fig. 5, a time and frequency mapping 500 of the DL sequence 400 transmission of fig. 4 is shown. Circle bracket 502 shows transmissions made from controller 102 and received at controller 102. Circle bracket 504 shows the transmissions made and monitored by repeater 106. Circle bracket 506 shows transmissions received at the SA104 and made from the SA 104.

As described above with reference to fig. 4, in the first slot 402, the data signals 404 and 406, transmitted over the frequencies f1 and f2, respectively, are unsuccessfully decoded at the first SA104 and the second SA 104. However, the data signals 404 and 406 are successfully monitored by the repeater 106. The data signal 408, transmitted over the frequency f3, is successfully decoded at the third SA 104. As shown, the frequencies f1, f2, and f3 in this example are in unlicensed bands.

As further described above with reference to fig. 4, in the second slot 402, NACK signals 410 and 412 are sent from the first SA104 and the second SA104 to the controller 102 over frequencies f4 and f5, respectively, and are monitored by the repeater 106. The ACK signal 414 is sent from the third SA104 to the controller 102 over frequency f6 and monitored by the repeater 106. As shown, the frequencies f4, f5, and f6 in this example are in unlicensed bands.

As further described above with reference to fig. 4, in the third time slot 402, the controller 102 and the repeater 106

send retransmissions

416 and 418 over frequencies f7 and f8, respectively, to the first SA and the second SA, respectively. In this example, the first SA104 and the second SA104 successfully decoded their

respective retransmissions

416 and 418. As shown, the frequencies f7 and f8 in this example are in licensed bands.

As further described above with reference to fig. 4, in the fourth time slot 402, the first SA104 and the second SA104 send

ACK signals

420 and 422, respectively, to the controller 102 over frequencies f10 and f11, respectively. The repeater 106 monitors the ACK signals 420 and 422 and may determine that the data signals 416 and 418 were successfully decoded. As shown, the frequencies f10 and f11 in this example are in licensed bands.

Referring now to fig. 6, an exemplary Uplink (UL) sequence 600 over the network 100 is shown. In a first slot 602 of the UL sequence 600, a first UL transmission 604 and a third UL transmission 606, sent from the first SA104 and the third SA104, respectively, to the controller 102, fail to be decoded at the controller 102. The first transmission 604 and the second transmission 608 are sent over frequencies f1 and f3, respectively. These failures may be due to obstructions, signal interference, etc., but this cannot be determined by the system. The second transmission 606, sent by the second SA104 over frequency f2, successfully reaches the controller 102. The frequencies f1, f2, and f3 may be in unlicensed bands. The repeater 106 monitors all three

transmissions

604, 606, and 608. As described above, the repeater 106 may determine that the time slot 602 is designated for data transmission from the SA104 to the controller 102 based on the global scheduling information, and may further determine that the transmission 604 over f1 was sent by the first SA104, the transmission 606 over f2 was sent by the second SA104, and the transmission 608 over f3 was sent by the third SA 104. The repeater 106 will decode and cache the monitored data signals. In some embodiments, the repeater 106 will only cache received signals that it recognizes as data signals after decoding.

In the second slot 602 of the UL sequence 600, the controller 102 sends NACK signals 610 and 614 on frequencies f4 and f6, respectively, to the first SA104 and the third SA104, respectively. The controller sends an ACK signal 612 to the second SA104 on frequency f 5. The frequencies f4, f5, and f6 may be in unlicensed bands. The repeater 106 monitors and decodes these NACK and ACK signals. Based on the global scheduling data, the relay 106 can determine that

NACKs

610 and 614 received on frequencies f4 and f6 are intended for the first SA104 and the third SA104, respectively, and that an ACK 612 received on frequency f5 is intended for the second SA 104. The reception of the

NACKs

610 and 614 indicates to the relay 106 and to the first SA104 and the third SA104 that a retransmission of the associated data signal is requested.

In the third slot 602 of the UL sequence 600, the repeater 106 and the first and

third SAs

104, 104 make any requested retransmissions. The relay may determine from the received

NACKs

610 and 614 in combination with the global scheduling data that the controller 102 is requesting to cause retransmission of data transmissions sent by the first SA104 and the third SA104 to the controller 102. The first SA104 and the third SA104 simply know from the

NACKs

610 and 614 that their data signals are required to be retransmitted because they can determine that only the controller 102 can have sent a NACK. The repeater 106 and the first and

third SAs

104, 104 know from the global scheduling data that the frequencies f7 and f9 are allocated for retransmission from the first and

third SAs

104, 104 during the third time slot 602. The repeater 106 and the first and

third SAs

104 and 104 therefore retrieve the data signals from their caches, re-encode the data signals, and retransmit the data signals as

retransmissions

616 and 618, respectively, to the controller 102 on frequencies f7 and f9, respectively. The frequencies f7 and f9 may be in licensed bands. In this example, the controller 102 successfully decodes all of the retransmitted data signals. In other embodiments, if the repeater 106 does not receive a NACK, the repeater 106 may determine that there is no need to store the data signal received in the second time slot 602. Thus, the repeater 106 may delete data signals from the cached data 307, mark the data signals as rewritable, or otherwise free up memory resources for other purposes.

Thus, in the fourth slot 602 of the UL sequence 600, the controller 102 sends ACK signals 620 and 622 over frequencies f10 and f12, respectively, to the first SA104 and the third SA104, respectively. The repeater 106 monitors the ACK signals 620 and 622 on frequencies f10 and f12, decodes the signals, and may determine from the global scheduling data that the signals must have been sent to the first SA104 and the third SA104, respectively. The relay 106 and the first and

third SAs

104 and 104 determine from the received

ACK signals

620 and 622 that the retransmission is successful and that no further retransmission is requested. In other examples, one or more retransmissions in the retransmission may fail, and the relay 106 and the first and

third SAs

104 and 104 may make second, third, or more retransmissions over different frequencies and in different time slots until the data is successfully received. When the system is initiated, the maximum number of retransmissions to attempt may be set across all devices in the network 100. In some embodiments, the number may be updated by transmissions from the controller 102 to the SA104 and repeater 106. Once the ACK signals 620 and 622 have been decoded, the repeater 106 may delete the data signals from the cached data 307, mark the data signals as rewritable, or otherwise free up memory resources for other purposes.

Referring now to fig. 7, a time and frequency mapping 700 of the transmission of UL sequence 600 shown in fig. 6 is shown. Circle bracket 702 shows transmissions made from controller 102 and received at controller 102. Circle brackets 704 show transmissions made by the repeater 106 and monitored by the repeater 106. Circle bracket 706 shows transmissions received at the SA104 and made from the SA 104.

As described above with reference to fig. 6, in the first time slot 602, the data signals 604 and 608 transmitted over the frequencies f1 and f3, respectively, are not successfully decoded at the controller 102. However, the data signals 604 and 608 are successfully monitored by the repeater 106. The data signal 606, which is transmitted above frequency f2, is successfully decoded at the controller 102. As shown, the frequencies f1, f2, and f3 in this example are in unlicensed bands.

As further described above with reference to fig. 6, in the second slot 602, NACK signals 610 and 614 are sent from the controller 102 to the first SA104 and the third SA104 over f4 and f6, respectively, and monitored by the repeater 106. The ACK signal 612 is sent from the controller 102 to the third SA104 on frequency f5 and monitored by the repeater 106. As shown, the frequencies f4, f5, and f6 in this example are in unlicensed bands.

As further described above with reference to fig. 6, in the third slot 602, the first and third SAs 104 and the repeater 106

send retransmissions

616 and 618 over frequencies f7 and f9, respectively, to the controller 102. In this example, controller 102 successfully decoded both

retransmissions

616 and 618. As shown, the frequencies f7 and f9 in this example are in licensed bands.

As further described above with reference to fig. 6, in the fourth time slot 602, the controller 102 sends ACK signals 620 and 622 over frequencies f10 and f12 to the first SA104 and the second SA104, respectively. The repeater 106 monitors the ACK signals 620 and 622 and can determine that the data signals 616 and 618 were successfully decoded. As shown, the frequencies f10 and f12 in this example are in licensed bands.

Referring now to fig. 8, a flow diagram of a method 800 of reducing errors in a wireless network is shown, in accordance with some aspects of the present disclosure. It is understood that additional steps may be provided before the steps of method 800, during the steps of method 800, and after the steps of method 800, and that some of the described steps may be replaced or eliminated with respect to other embodiments of method 800. For example, the method 800 may be modified to include aspects of the techniques for reducing errors in wireless communications described in other portions of this disclosure.

Beginning at block 802, a first wireless device, such as relay device 106, receives a data signal on a first frequency resource during a first time period. A data signal is sent from a second wireless device, such as controller 102 or SA104, to a third wireless device, such as SA104 or controller 102.

At block 804, the repeater 106 decodes the data signal. At block 806, the repeater 106 caches the decoded data, e.g., by storing the data in the memory 304 as cached data 307. At block 808, the repeater 106 receives the ACK/NACK signal during the second time period. At block 810, the repeater 106 decodes the ACK/NACK signal. At block 812, the repeater 106 caches the decoded ACK/NACK signal, for example, by storing the ACK/NACK signal in the memory 304. In some embodiments, the repeater 106 does not cache the decoded ACK/NACK signal, but moves directly from block 810 to decision block 814. At decision block 814, the repeater 106 determines whether a NACK signal was received.

At block 816, if a NACK is received, the repeater 106 retrieves the cached data signal and re-encodes the data signal for retransmission on the second frequency resource. At block 818, the repeater 106 retransmits the data signal on the second frequency resource to the third wireless device during the third time period.

At block 820, after retransmission of the re-encoded data signal, the repeater 106 may discard the cached data signal from its cache. When the repeater receives a subsequent data signal, the method returns to block 802.

Returning to decision block 814, if the repeater 106 determines that a NACK has not been received (e.g., an ACK has been received), the method moves to block 820 and the cached data is discarded from the cache. When the repeater receives a subsequent data signal, the method returns to block 802.

Information and signals may be represented using any of a variety of different technologies and techniques. For example, data, instructions, commands, information, signals, bits, symbols, and chips that may be referenced throughout the above description may be represented by voltages, currents, electromagnetic waves, magnetic fields or particles, optical fields or particles, or any combination thereof.

The various illustrative blocks and modules described in connection with the disclosure herein may be implemented or performed with a general purpose processor, a DSP, an ASIC, an FPGA or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. A general-purpose processor may be a microprocessor, but in the alternative, the processor may be any conventional processor, controller, microcontroller, or state machine. A processor may also be implemented as a combination of computing devices (e.g., a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration.

The functions described herein may be implemented in hardware, software executed by a processor, firmware, or any combination thereof. If implemented in software executed by a processor, the functions may be stored on or transmitted over as one or more instructions or code on a computer-readable medium. Other examples and implementations are within the scope of the disclosure and the appended claims. For example, due to the nature of software, the functions described above can be implemented using software executed by a processor, hardware, firmware, hard-wired, or a combination of any of these. Features used to implement functions may also be physically located at various locations, including being distributed such that portions of functions are implemented at different physical locations. Further, as used herein, including in the claims, a "or" (e.g., a list of items prefaced by a phrase such as "at least one of" or one or more of ") as used in a list of items indicates an inclusive list such that, for example, a list of [ A, B or C ] means a or B or C or AB or AC or BC or ABC (i.e., a and B and C). As those skilled in the art will appreciate so far and depending on the specific application at hand, many modifications, substitutions and variations in the materials, devices, configurations and methods of use of the apparatus of the present disclosure, as well as many modifications, substitutions and variations in the materials, devices, configurations and methods of use of the apparatus of the present disclosure, may be made without departing from the spirit and scope thereof. In view of this, since the particular embodiments shown and described herein are to be considered as examples only, the scope of the present disclosure should not be limited to the described embodiments, but rather should be fully commensurate with the appended claims and their functional equivalents.

Claims

1. A method of wireless communication, comprising:

receiving, at a first wireless communication device, a data signal, the data signal transmitted on a first frequency resource from a second wireless communication device to a third wireless communication device;

receiving an ACK/NACK signal at the first wireless communication device, the ACK/NACK signal being transmitted from the third wireless communication device to the second wireless communication device;

determining, at the first wireless communication device, whether the ACK/NACK signal is a NACK signal;

determining, at the first wireless communication device, a scheduled time for the second wireless communication device to retransmit the data signal and a second frequency resource, wherein the second frequency resource is different from the first frequency resource, wherein the first frequency resource is in an unlicensed frequency band and the second frequency resource is in a licensed frequency band; and

transmitting the data signal from the first wireless communication device to the third wireless communication device at the scheduled time on the second frequency resource in response to determining that the ACK/NACK signal is a NACK signal.

2. The method of claim 1, further comprising:

receiving, at the first wireless communication device, scheduling information for the second wireless communication device and the third wireless communication device, the scheduling information including the scheduled time and second frequency resources.

3. The method of claim 2, wherein:

the scheduling information at least includes:

the second wireless communication device is scheduled to transmit the data signal to the third wireless communication device on the first frequency resource during a first time period,

the third wireless communication device is scheduled to transmit the ACK/NACK signal to the second wireless communication device during a second time period after the first time period, an

The second wireless communication device is scheduled to retransmit to the third wireless communication device at the scheduled time on the second frequency resource during a third time period after the second time period.

4. The method of claim 1, further comprising:

receiving a synchronization beacon at the first wireless communication device; and

maintaining timing synchronization with the second wireless communication device and the third wireless communication device using the synchronization beacon.

5. The method of claim 4, wherein the synchronization beacon is received periodically at a pre-specified time interval.

6. The method of claim 1, further comprising:

decoding the data signal at the first wireless communication device;

caching the decoded data signal at the first wireless communication device;

decoding the ACK/NACK signal at the first wireless communication device; and

retrieving the cached data signal at the first wireless communication device if the ACK/NACK signal is determined to be a NACK signal.

7. The method of claim 1, further comprising:

encoding the data signal at the first wireless communication device prior to transmitting the data signal to the third wireless communication device.

8. The method of claim 1, wherein:

the first wireless communication device is a wireless relay device,

the second wireless communication device is at least one of a sensor device or an actuator device, an

The third wireless communication device is a controller device.

9. The method of claim 1, wherein:

the first wireless communication device is a wireless relay device,

the second wireless communication device is a controller device, and

the third wireless communication device is at least one of a sensor device or an actuator device.

10. A method of wireless communication, comprising:

receiving, at a first wireless communication device, a notification that a data signal is to be transmitted from a second wireless communication device to the first wireless communication device on a first frequency resource during a first time period;

transmitting, from the first wireless communication device during a second time period, a NACK indicating that the data signal was not correctly received from the second wireless communication device; and

receiving, at the first wireless communication device, the data signal on a second frequency resource at a scheduled time during a third time period from a third wireless communication device and on the second frequency resource and at the scheduled time from the second wireless communication device, wherein the second frequency resource is different from the first frequency resource, wherein the first frequency resource is in an unlicensed frequency band and the second frequency resource is in a licensed frequency band.

11. The method of claim 10, further comprising:

12. The method of claim 10, wherein:

the first wireless communication device is at least one of a sensor device or an actuator device,

the second wireless communication device is a controller device, and

the third wireless communication device is a wireless relay device.

13. The method of claim 10, wherein:

the first wireless communication device is a controller device,

The third wireless communication device is a wireless relay device.

14. A first wireless communications device, comprising:

a transceiver configured to receive a data signal transmitted from a second wireless communication device to a third wireless communication device on a first frequency resource, the transceiver further configured to receive an ACK/NACK signal transmitted from the third wireless communication device to the second wireless communication device; and

a processor configured to determine whether the ACK/NACK signal is a NACK signal, and a scheduled time and a second frequency resource for the second wireless communication device to retransmit the data signal, wherein the second frequency resource is different from the first frequency resource, wherein the first frequency resource is in an unlicensed frequency band and the second frequency resource is in a licensed frequency band,

wherein the transceiver is further configured to: transmitting the data signal to the third wireless communication device at the scheduled time on the second frequency resource in response to the processor determining that the ACK/NACK signal is a NACK signal.

15. The first wireless communications device of claim 14, wherein the transceiver is further configured to receive scheduling information for the second and third wireless communications devices, the scheduling information including the scheduled time and second frequency resources.

16. The first wireless communications device of claim 15, wherein:

the scheduling information at least includes:

17. The first wireless communications device of claim 14, wherein:

the transceiver is further configured to receive a synchronization beacon, an

The processor is further configured to maintain timing synchronization with the second wireless communication device and the third wireless communication device using the synchronization beacon.

18. The first wireless communications device of claim 17, wherein the transceiver is further configured to receive the synchronization beacon at a pre-specified time interval.

19. The first wireless communications device of claim 14, wherein:

the processor is further configured to decode the data signal,

the processor is further configured to cache the decoded data signal,

the processor is further configured to decode the ACK/NACK signal, an

The processor is further configured to retrieve the cached data signal if the ACK/NACK signal is determined to be a NACK signal.

20. The first wireless communication device of claim 14, wherein the processor is further configured to encode the data signal prior to transmitting the data signal to the third wireless communication device.

21. The first wireless communications device of claim 14, wherein:

the first wireless communication device is a wireless relay device,

The third wireless communication device is a controller device.

22. The first wireless communications device of claim 14, wherein:

the first wireless communication device is a wireless relay device,

the second wireless communication device is a controller device, and

23. A first wireless communications device, comprising:

a transceiver configured to:

receiving a notification that a data signal is to be transmitted from a second wireless communication device to the first wireless communication device on a first frequency resource during a first time period;

transmitting a NACK indicating that the data signal was not correctly received from the second wireless communication device during a second time period, an

Receiving the data signal on a second frequency resource at a scheduled time during a third time period from a third wireless communication device and on the second frequency resource and at the scheduled time from the second wireless communication device, wherein the second frequency resource is different from the first frequency resource, wherein the first frequency resource is in an unlicensed frequency band and the second frequency resource is in a licensed frequency band.

24. The first wireless communications device of claim 23, wherein:

the transceiver is further configured to receive a synchronization beacon, an

The first wireless communication device also includes a processor configured to maintain timing synchronization with the second wireless communication device and the third wireless communication device using the synchronization beacon.

25. The first wireless communications device of claim 23, wherein:

the second wireless communication device is a controller device, and

the third wireless communication device is a wireless relay device.

26. The first wireless communications device of claim 23, wherein:

the first wireless communication device is a controller device,

The third wireless communication device is a wireless relay device.